Looks good. Now adapt a linear actuator and get rid of the lever.
Now after you use the blade for a while, post back with the results. There are a lot of naysayers her who think a sleeve hitch on a lawn tractor is a big mistake. I for one, think that if you are CAREFUL and realize the strengths and weaknesses of the machine you will be just fine. I'm working on a similar project for a LT1050.